Roots growing up to surface

This
4 foot deep trench was dug six years after planting a row of trees two
and one half feet from Biobarrier™. The 12-inch deep barrier is six
inches behind the soil wall on the right side of the trench. Roots (painted
white) grew under the barrier and can be seen distributed at all depths
on the right side of the trench (see arrows).
The barriers appeared
to be deflecting roots to deeper soil layers compared to trees without
the barriers. However, six feet from the barrier (left wall of the trench)
most roots were in the top 12 inches of soil.